Just curious to know if anyone has ever heard anything unusual above 108 MHz, pirate or otherwise. I found this link to a station supposedly broadcasting on 108.3 MHz in Minnesota: http://koehfm.com/index.php/about-us
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Above 108 MHz...ever hear anything unusual here?
- Thread starter Buckeyes2001
- Start date
I think KOEH on 108.3 is a hoax. No FCC licensed broadcasters above 107.9. If there was a "pirate" in the aircraft band, the FCC and FAA would be after them probably quicker than if they were in the FM broadcast band. Also, my digital radios do not tune to 108.3. Who would be listening to them?
What about 107.9 FM IBOC stations near airports?
So far I've come up with...
50kW WEBE 3 miles from Igor I Sikorsky Memorial Airport near Bridgeport, CT
100kW KMLE 7.6 miles from Phoenix Sky Harbor International Airport near Phoenix, AZ
50kW KDND 5.9 miles from Sacramento International Airport near Sacramento, CA
and 20.5kW WXKS 3.4 miles from Logan International Airport near Boston, MA
My search wasn't completely exhaustive, though. I wonder if there are any (preferably International) airports located such that the entire airport property is within the 110-120 dBµ contour of a class-C FM IBOC station on 107.9 running -6dBc?
(or at least close enough so that on something like a Tecsun PL-390 it wipes out reception of the rest of the FM band)?
So far I've come up with...
50kW WEBE 3 miles from Igor I Sikorsky Memorial Airport near Bridgeport, CT
100kW KMLE 7.6 miles from Phoenix Sky Harbor International Airport near Phoenix, AZ
50kW KDND 5.9 miles from Sacramento International Airport near Sacramento, CA
and 20.5kW WXKS 3.4 miles from Logan International Airport near Boston, MA
My search wasn't completely exhaustive, though. I wonder if there are any (preferably International) airports located such that the entire airport property is within the 110-120 dBµ contour of a class-C FM IBOC station on 107.9 running -6dBc?
(or at least close enough so that on something like a Tecsun PL-390 it wipes out reception of the rest of the FM band)?I did a license search at this site for anything licensed to 108.3 and found only aircraft stuff:
http://wireless2.fcc.gov/UlsApp/UlsSearch/searchAdvanced.jsp
Not sure what radios would even be able to tune 108.3, probably analog tuning sets where you can tune a bit beyond 108, but no digitally tuned set I've ever seen got 108.3.
Theres 50kw 107.9 WWHT Syracuse, NY running IBOC but its about 10 miles from Hancock International airport.
http://wireless2.fcc.gov/UlsApp/UlsSearch/searchAdvanced.jsp
Not sure what radios would even be able to tune 108.3, probably analog tuning sets where you can tune a bit beyond 108, but no digitally tuned set I've ever seen got 108.3.
pianoplayer88key said:
Theres 50kw 107.9 WWHT Syracuse, NY running IBOC but its about 10 miles from Hancock International airport.
There's nothing in the aircraft band right adjacent to the FM band so the IBOC overflow shouldn't matter.
I've got an old Panasonic shortwave portable that is analog w/ digital readout that tunes to just past 109 MHz, but I've never heard anything except the occasional mixing of strong locals.
I've got an old Panasonic shortwave portable that is analog w/ digital readout that tunes to just past 109 MHz, but I've never heard anything except the occasional mixing of strong locals.
i used to have a radio shack archer "jetstream" pocket radio that had an analog tuner from 108 to 138? mhz. Aside from plane traffic there were a couple frequencies with a reoccurring sound sequence. It basically was a series of beeps followed by some garbled "data" type noises. Im assuming it was some sort of radar? navigation aid? this was back in the 80s/90s.
Not only does normal radio not exist beyond 107.9, but the town doesn't exist. While KFAI is a real station, it only exists in the Twin Cities and online. The larger scale map show both I-35 and I-94 meeting outside of town. The only two places they intersect is in downtown Minneapolis and St. Paul. The whole website looks like a visualization of Garrison Kellior's Prairie Home Companion.
Back in the late 70's and 80's, there were some "extra-curricular" stations that occupied the area of 108.3 and 108.5 MHz. But ever since PLL digital tuning came of age in the mid 80's, those operations faded into oblivion because the radios that were being made after the mid 80's did not venture that high up on the band. SO, many of these "extra-curricular" stations moved down the dial to the standard FM band (87.7 - 107.9 MHz). You really can't miss them. They (the pirates) stand out like sore thumbs. If you still have a radio that goes above 108.1+, you'll more than likely hear navigation beacons operating in the AM mode. Like the NDB's (non-directional beacons) operating below 500 kHz, these too have Morse Code identifiers as well. Check it out.
pianoplayer88key said:What about 107.9 FM IBOC stations near airports?
So far I've come up with...
50kW WEBE 3 miles from Igor I Sikorsky Memorial Airport near Bridgeport, CT
100kW KMLE 7.6 miles from Phoenix Sky Harbor International Airport near Phoenix, AZ
50kW KDND 5.9 miles from Sacramento International Airport near Sacramento, CA
and 20.5kW WXKS 3.4 miles from Logan International Airport near Boston, MA
My search wasn't completely exhaustive, though. I wonder if there are any (preferably International) airports located such that the entire airport property is within the 110-120 dBµ contour of a class-C FM IBOC station on 107.9 running -6dBc?
WEBE 108 doesn't broadcast in HD
Hello, my original post disappeared so I’ll try again. My IBOC comments below pertain to FM IBOC not AM IBOC. I found some references to occasional pirate broadcasters on 108.1 MHz but there are no commercial broadcasters licensed for 108+ MHz in the US.
The FM Broadcast band in the US starts at 88.0 and ends at 108.0 MHz. FM stations are required to fit within their assigned 200 kHz channel. An FM station on 107.9 MHz is licensed to channel 300 which begins at 107.8 and ends at 108.0. The FM station’s signal should fit within that 200 kHz channel if they are transmitting with or without IBOC. Any signal transmitted outside of that channel must be at a much lower strength. So for all intents and purposes, an FM station on 107.9 is not transmitting any significant signal below 107.8 or above 108.0 MHz.
The aeronautical band begins at 108.0 MHz. The lowest frequency used for VOR/ILS/TACAN signals is called channel 018X and is at 108.10 MHz. Channel 018X and 018Y (108.15 MHz) are used for ground testing by avionics technicians. The first aeronautical frequency that is in actual use by aircraft is channel 019X at 108.20 MHz. Any interference to aviation at 108.20 or higher might bring on the wrath of the FAA, FCC and FBI.
Go to this site and enter 108.20. http://www.airnav.com/navaids/
You will find VOR transmitters on that frequency all across the US.
Most modern avionics equipment is built with high pass filters and extra circuitry to help eliminate the possible problems caused by strong FM broadcast stations on nearby frequencies. If you need more information, do a search for “FM Immunity”.
Most consumer FM broadcast radios do not have very good IF filters and circuitry. FM stations, especially those stations broadcasting with IBOC, will cause problems on adjacent channels on our FM radios. For the most part, this interference is caused in the receiver and not by the FM transmitting station. There are some FM radios with digital signal processing that do not seem to have these problems and can pick up stations adjacent to the IBOC stations.
As I’ve mentioned, FM IBOC stations must fit within the FM station’s channel. The website below has a fairly technical discussion about the IBOC FM mask and what the IBOC stations must do to main compliance.
http://radiomagonline.com/digital_radio/hd_radio/iboc_mask_compliance_1011/
Finally, as far as I can tell, FM IBOC stations are authorized a maximum of -10 dBc signal strength on their IBOC signal. This is allowed by the FCC on a case by case basis and the station must reduce their IBOC signal if there are confirmed interference problems. -10 dBc is 10% of their analog signal so a 25,000 watt station could be allowed to transmit a maximum of 2,500 watt IBOC signal. The IBOC signal at whatever power level still must fit within the mask as detailed above.
Bottom line, FM stations on 107.9 with or without IBOC should not be causing any problems in the aircraft bands if they are operating properly.
Y’all have a good weekend. -Bill
The FM Broadcast band in the US starts at 88.0 and ends at 108.0 MHz. FM stations are required to fit within their assigned 200 kHz channel. An FM station on 107.9 MHz is licensed to channel 300 which begins at 107.8 and ends at 108.0. The FM station’s signal should fit within that 200 kHz channel if they are transmitting with or without IBOC. Any signal transmitted outside of that channel must be at a much lower strength. So for all intents and purposes, an FM station on 107.9 is not transmitting any significant signal below 107.8 or above 108.0 MHz.
The aeronautical band begins at 108.0 MHz. The lowest frequency used for VOR/ILS/TACAN signals is called channel 018X and is at 108.10 MHz. Channel 018X and 018Y (108.15 MHz) are used for ground testing by avionics technicians. The first aeronautical frequency that is in actual use by aircraft is channel 019X at 108.20 MHz. Any interference to aviation at 108.20 or higher might bring on the wrath of the FAA, FCC and FBI.
Go to this site and enter 108.20. http://www.airnav.com/navaids/
You will find VOR transmitters on that frequency all across the US.
Most modern avionics equipment is built with high pass filters and extra circuitry to help eliminate the possible problems caused by strong FM broadcast stations on nearby frequencies. If you need more information, do a search for “FM Immunity”.
Most consumer FM broadcast radios do not have very good IF filters and circuitry. FM stations, especially those stations broadcasting with IBOC, will cause problems on adjacent channels on our FM radios. For the most part, this interference is caused in the receiver and not by the FM transmitting station. There are some FM radios with digital signal processing that do not seem to have these problems and can pick up stations adjacent to the IBOC stations.
As I’ve mentioned, FM IBOC stations must fit within the FM station’s channel. The website below has a fairly technical discussion about the IBOC FM mask and what the IBOC stations must do to main compliance.
http://radiomagonline.com/digital_radio/hd_radio/iboc_mask_compliance_1011/
Finally, as far as I can tell, FM IBOC stations are authorized a maximum of -10 dBc signal strength on their IBOC signal. This is allowed by the FCC on a case by case basis and the station must reduce their IBOC signal if there are confirmed interference problems. -10 dBc is 10% of their analog signal so a 25,000 watt station could be allowed to transmit a maximum of 2,500 watt IBOC signal. The IBOC signal at whatever power level still must fit within the mask as detailed above.
Bottom line, FM stations on 107.9 with or without IBOC should not be causing any problems in the aircraft bands if they are operating properly.
Y’all have a good weekend. -Bill
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